Energy loss of protons at low velocities in Pd and Au polycrystalline thinfilms

Experimental results on proton energy loss distributions obtained by ion tr ansmission measurements in Pd polycrystalline thin films are reported. Devi ations from the proportionality behavior of the energy loss as a function o f the ion velocity is observed. These results are compared with similar mea surements in Au. A theoretical model previously developed is used to explai n the observed velocity dependence. General trends on the relationship betw een the electronic density of states of these metals and the non-proportion ality of the energy loss with ion velocity are discussed. (C) 2000 Elsevier Science B.V. All rights reserved.